Field of the Invention
Embodiments of the present invention generally relate to apparatus and methods for determining parameters of a fluid in a wellbore and, more specifically, an apparatus and method for determining parameters in cemented multi-zone completions.
Description of the Related Art
In the hydrocarbon industry, there is considerable value associated with the ability to monitor the flow of hydrocarbon products in every zone of a production tube of a well in real time. For example, downhole parameters that may be important in producing from, or injecting into, subsurface reservoirs include pressure, temperature, porosity, permeability, density, mineral content, electrical conductivity, and bed thickness. Downhole parameters may be measured by a variety of sensing systems including acoustic, electrical, magnetic, electro-magnetic, strain, nuclear, and optical based devices. These sensing systems are intended for use between the zonal isolation areas of the production tubing in order to measure fluid parameters adjacent fracking ports. Fracking ports are apertures in a fracking sleeve portion of a production tube string that open and close to permit or restrict fluid flow into and out of the production tube.
One challenge of monitoring the flow of hydrocarbon products arises where cement is used for the zonal isolation. In these instances, the annular area between the production tubing and the wellbore is filled with cement and then perforated by a fracking fluid. As a result, sensors located on an exterior surface of the tubing may not be in direct fluid communication with the fluid flowing into and out of the perforated cement locations. Another challenge arises where the sensor spacing is not customized to align with the zonal isolation areas for each drilling operation. For example, the sensing system may include an array of sensors interconnected by a sensing cable. The length of the sensing cable between any two sensors is set and not adjustable. Conversely, the distance between each zonal isolation area varies for each drilling operation. As a result, the sensing system's measurements may be inaccurate due to the sensor's location along the production tube.
What is needed are apparatus and methods for improving the use of sensing systems with cemented zonal isolations.